1- Pizza crust first because those who are maakpid like Mishna Berrurah and Rav Shlomo Zalman to make Hamotzie on Pizza they want to make the Bracha on plain crsut wiht no sauce or chgees.
2- In Kabala there are 7 foods one eats with his hands, no other. Although we are not on that madraygah, let us be careful not to mock.
3- I have seen Gedolim and Rabbanim chashuvim eat a sandwich with fork and kniofe. My Rebbi exlained that it is not proper to put food in mouth, bite and pull some out. From mussar point of view It is uncouth and form Kabbalistic point of view is a rejection of portions of food which then would never be eaten. Breaking off pieces and eating a piece at a time is the proper way to live on the higher standards.
4- I have seen some great people do the same with Matzah and Korach as well. Great people are consistent.
5- We need to avoid demonstrating our ignorance by criticizing, mocking, being sarcastic without checking things out. Yiddishkeit is a multi level experiential possibility. Not everyone is expected to be the same and different standards DO apply to different people. MOst certainly laytzanus is not a virtue.